Abstinence from smoking produces aversive symptoms that prompt relapse, often within the first week following a quit attempt. Clarifying the neurobiological and behavioral underpinnings of these early abstinence symptoms is, therefore, critical to develop more efficacious treatments. The proposed Center for Interdisciplinary Research on Nicotine Addiction (CIRNA) extends nine years of research conducted in the Transdisciplinary Tobacco Use Research Center (TTURC) at UPENN. Spanning from preclinical to clinical studies, CIRNA includes a highly interactive set of projects and cores that seek to: (1) discover the cellular, molecular, neural, and behavioral basis of early nicotine abstinence effects that contribute to relapse;(2) identify brain and behavioral mechanisms through which efficacious therapies modulate these processes;and (3) validate novel medication screening approaches. Project 1 uses neurobiology and pharmacology to elucidate the molecular and behavioral basis of emotional and cognitive symptoms of nicotine abstinence and re-exposure in a mouse model. Project 2 uses electrophysiology and pharmacology to explore the effects of nicotine abstinence and re-exposure on sensory processing in key brain regions in mice. Project 3 uses human neuroimaging to examine the neural substrates of early abstinence symptoms and medication response. Project 4 extends this work by validating novel approaches to improve the sensitivity of early human medication screening paradigms for nicotine dependence. Shared resources, including an Administrative Core, a Data Management and Biostatistics Core, and a Biospecimen Core provide value-added, as well as support for a comprehensive data sharing plan. A Career Development Core promotes involvement of post-doctoral fellows and junior investigators in these projects, and supports pilot projects to facilitate career development. Thus, the CIRNA addresses the clinically important problem of nicotine dependence using innovative multidisciplinary approaches, with the ultimate goal of developing more efficacious medications for tobacco dependence and prevention of tobacco-related disease. The CIRNA is proposed to replace the TTURC, since this NIH initiative is ending. CENTER CHARACTERISTICS